China is undergoing a rare leadership transition at a time of rising social tensions. Inside the world's biggest security state

Heir apparent Xi Jinping, seen here with China's other top leaders at a National Day celebration, is poised to take the reins in November

On Oct. 1, the 63rd anniversary of the founding of the People's Republic of China, nine black-haired men in dark suits stood solemnly in Beijing's Tiananmen Square. Looming over the clutch of men who constitute China's current and future leadership were dozens of security cameras affixed to lampposts. Goose-stepping soldiers marched past. As always, a giant portrait of Chairman Mao Zedong, the founder of the People's Republic, gazed over the square, as did hundreds of plainclothes police with their telltale buzz cuts and watchful eyes. Despite the lavish floral displays and representatives of ethnic minorities in colorful garb, the square bristled...